Thermostatic safety valve control



Aug. 21, .1956

J. A. NELSON ETAL 2,759,675 THERMOSTATIC SAFETY VALVE CONTROL Filed Sept. 14, 1950 II" I g INVENTOR.

ATT0RNEY United States Patent 'II-IERMOSTATIC SAFETY VALVE CONTROL James A. Nelson, Elmhurst, and Joseph M. Algino, Chicago, Ill., assignors to Cribben and Sexton Company, Chicago, 111., a corporation of Illinois Application September 14, 1950, Serial No. 184,843

7 Claims. (Cl. 236-4) This invention relates to a safety valve control and is particularly useful in the control of the flow of gas for the heating of space, as for example, an oven space, by controlling the flow of gas to the main heating burner therefor.

An object of the invention is to provide, in a single valve control structure, means for performing the functions of a modulating thermostat and a safety valve. A still further object is to provide in a heating device a single control for one flow of gas with automatic selection of motivating force of prime importance at any particular time, while at the same time controlling the flow of gas to the heating burner. Yet another object is to provide a valve structure equipped with an inlet and outlet and a movable valve for controlling either the inlet or the outlet, the valve being under the combined influence or action of an expansion fluid mechanism or thermal responsive element actuated by a burner and an expansion fluid mechanism or thermal responsive element actuated by a space thermostat, i. e., the combined influence or action of an expansion fluid mechanism or thermal responsive element actuated by a direct flame temperature. Yet another object is to provide a movable valve for controlling the flow of gas to a burner, means being provided for closing the valve when the burner is extinguished and for rendering operative a second control device when the burner is ignited, the second control device being actuated by a space thermostat or the like. A further advantage is that the control accomplished in the above structure is effected through a single valve in co-action with its valve seat; in other words, we provide a structure having one control point selectively acted upon by the requirements of the space to be heated or by the requirements of a source of ignition. In other words, we combine the control forces from the space to be heated and the source of ignition so as to effect a control of the flow of gas through a single control point by permitting selective action of the abovementioned controlled forces. Other specific objects and advantages will appear as the specification proceeds.

The invention is shown in an illustrative embodiment by the accompanying drawing in which Fig. l is a longitudinal sectional view of a valve control device embodying our invention; and Fig. 2, a view similar to Fig. 1 but showing the valve in opened position.

In the illustration given, We provide a hollow valve casing 10 provided with an inlet 11 and an outlet 12. The inlet port 11 may be provided with a conduit 13 leading to a source of gas while the outlet port 12 may be provided with a conduit 14 leading to a main burner or other type of burner (not shown) to which the flow of gas is to be controlled.

We provide a valve 15 for closing either the inlet port or the out-let port, and in the specific illustration given the valve is supported for sealing the outlet port 12. The valve 15 is provided with a stem 16 equipped at an intermediate point with a collar 17. About the stem 16 2,759,675 Patented Aug. 21, 1956 is slidably supported a sleeve 18 equipped with a depending stud 19 adapted to engage the collar 17 on one side. The sleeve 18 may be slidably supported within the track members 20 secured to the casing, and the stem 16 may be slidably supported within the spider arms 21 mounted within sleeve 18.

At one end of the casing 10, and preferably positioned therein, is a conventional thermostat bellows or diaphragm 22 connected to a link 23 by means of a pivot pin. Secured to the link 23 is a bell crank 23a supported for pivotal movement about the pivot pin or post 23b. A link or lever 24 is connected at its upper end to the bell crank 23a, and at its lower end is connected by a short link 25 to the stem 16. If desired, the lever 24 may be provided with a bearing portion 24a adapted to engage the fulcrum members or fulcrum points 26 and 27.

It is important that the fulcrum points 26 and 27 engage the link 24 at the same point no matter what the temperature conditions of either the space being heated which controls the bellows 22 or the pilot burner which, through an arrangementto be described hereinafter, controls the sleeve 18. This is important since it is necessary that lever 24 provide the same linear motion to the rod 16 per unit of bellows movement no matter what the starting point for that movement may be. This results in maintaining accurate calibration of the thermostat which calls for a given valve opening with a given bellows opening or position.

It is intended, therefore, that the point of contact between the fulcrums 26 and 27 and the lever 24 shall be on a line through points 26 and 27, or be arranged to be picked up by fulcrum points 26 and 27 and brought into that line when said points move to complete the lever system by hearing against the enlargement 24a of the lever 24. To further this result, the lever 24 may be provided with an elongated slot 24b through which that lever is connected to the bell crank. Preferably, the short link 25 is provided with a forwardly extending flange 25a that projects under the stem 16.

A compression spring 28 seats at one end against a depending abutment 29 on the sleeve 18, and provides a biasing force normally urging the sleeve toward the outletend of the casing 10, as shown in Figure 1. In this position, the stud 19 engages the collar 17 of the valve stem 16, and thus maintains the valve 15 in sealing engagement with the outlet port 12.

A tube 30 adapted to contain an expansion fluid, such as mercury vapor, is provided with a bulb end 31 adapted to be located adjacent a pilot burner (not shown) that is supplied with fuel through independent valve controlled conduits which may be wholly conventional and, since well known in the art, are not illustrated nor described. The tube 30 communicates with a movable diaphragm 32 located interiorly of the casing 10, and the diaphragm is connected by link 33 to one arm of a pivotally mounted bell crank 34. The other arm of the bell crank is connected by a link 35 to a slidably mounted sleeve 18.

Operation In the operation of the device, the parts in their starting position are shown in Fig. 1. Valve 15 is closed. Since the diaphragm 32 is collapsed, this allows compression spring 28 to carry sleeve 18 and valve rod 16 to the extreme right. The position of the link 24 and thermostat bellows 22 is of no importance at this stage because the fulcrum point 26 is out of contact with the lever or link 24.

It will be understood that some manual or automatic means will bring about the ignition of the pilot burner, etc., the heat from which would be transmitted to the bulb 31, and the expansion fluid within the bulb and tube 30 will actuate the diaphragm 32 causing it to rise, as illustrated in Fig. 2. The upward movement of the diaphragm 32 moves the bell crank 34 to the position illustrated in Fig. 2, and moves the slidable tube and slidable sleeve 18 in a rearward direction so as to bring the fulcrum point 26 into contact with the lever 24. At this point the valve stem 16 is rendered independent of the sleeve 18, and its motion is controlled solely by the lever 24 which is fulcrumed upon the points 26 and 27. The valve will now tend to open or close under action of the bellows 22 and lever 24 and in response to the thermostat located in the heated space.

As long as the pilot burner or burner heating the bulb 31 is constantly burning, the position shown in Fig. 2 will be maintained, but should the pilot flame become extinguished, the diaphragm 32 will collapse to the position shown in Fig. 1 and the sleeve 18 will move to the right bringing the valve into sealing relation with the outlet 12. The control described thus provides, with one valve and two counter-acting forces, a mechanism to provide a modulating control and an on-off control, depending upon which force is in excess of the other.

It will be understood that while the device has been described in connection with fuel gas, the structure is applicable to other uses. Further, instead of using the diaphragms and other specific devices, equivalent movable structures which are responsive to temperature changes may be used.

While in the foregoing specification we have set out a specific structure in considerable detail for the purpose of illustrating embodiments of our invention, it will be understood that such details of structure may be varied widely by those skilled in the art without departing from the spirit of our invention.

We claim:

1. A safety valve control device comprising a hollow casing equipped with inlet and outlet ports, a valve adapted to close one of said ports and provided with a stem extending rearwardly therefrom, a movablymounted sleeve enclosing said stern, interlocking connections between said sleeve and said stern causing said sleeve stem to move together when said sleeve is moved to close said valve but allowing said stem to move independently through a range of positions when the sleeve is moved in the opposite direction, a spring normally urging said sleeve in said valve-closing direction, a diaphragm equipped with a conduit for receiving expansion fluid, linkage between said diaphragm and said sleeve for moving said sleeve away from valve-closing position and compressing said spring, a second diaphragm equipped with a tube for receiving expansion fluid, and linkage connecting said second diaphragm and said valve stem for the actuation of said valve stem when the same is freed from said sleeve.

2. A safety valve control device comprising a hollow casing equipped with inlet and outlet ports, a valve adapted to close one of said ports and provided with a stem extending rearwardly therefrom, a movablymounted sleeve enclosing said stern, interlocking connections between said sleeve and said stem causing said sleeve and stem to move together when said sleeve is moved to close said valve but allowing said stem to move independently through a range of positions when the sleeve is moved in the opposite direction, a spring normally urging said sleeve in said valve-closing direction, a diaphragm equipped with a conduit for receiving expansion fluid, linkage between said diaphragm and said sleeve for moving said sleeve away from valve-closing position and compressing said spring, a second diaphragm equipped with a tube for receiving expansion fluid, a stern connected to said second diaphragm, a lever connecting said second diaphragm stem with said valve stem, and a fulcrum carried by said sleeve and engageable with said lever when said sleeve is moved away from valve-closing position.

3. A safety valve control? device comprising a hollow casing equipped with inlet and outlet ports, a valve adapted to close one of said ports and provided with a stern extending rearwardly therefrom, a movably-mounted sleeve enclosing said stern, interlocking connections between said sleeve and said stem causing said sleeve and stem to move together when said sleeve is moved to close said valve but allowing. said stem to -move independently through a range of positions when the sleeve is moved in the opposite direction, a spring normally urging said sleeve in said valve-closing direction, a diaphragm equipped with a conduit for receiving expansion fluid, linkage between said diaphragm and said sleeve for moving said sleeve away from valve-closing position and compressing said spring, a second diaphragm equipped with a tube for receiving expansion fluid, a stem connected to said second diaphragm, a lever connecting said second diaphragm stem with said valve stem, a fulcrum carried by said sleeve and engageable with said lever when said sleeve is moved away from valve-closing position, and a second fulcrum carried by said casing in alignment with the fulcrum of said sleeve whereby when said sleeve fulcrum is moved intoengagement with said lever, said lever is free to swing upon both fulcrums in the actuation of said valve stem.

4-. In a safety valve control device, a hollow casing equipped with inlet and outlet ports, a valve for closing one of said ports and equipped with a slidably-mounted stem, a floating sleeve enclosing said stem and equipped with a depending stud, a collar carried by said stern between said stud and said valve whereby when said sleeve is moved towards said valve, said valve is brought into sealing engagement with said port, a spring normally urging said sleeve toward valve-closing position, a lever connected to said stem, a temperature-responsive member for moving the outer part of said lever, a fixed fulcrum carried by said casing on one side of said lever, a movable fulcrum carried by said sleeve on the other side of said lever, and temperature-responsive means for moving said sleeve to bring said lever into engagement with said movable and fixed fulcrumsfor the actuation of said valve stem and to permit said valve to be moved through a range of positions.

5. A safety valve device having a valve selectively responsive to the one of two motivating forces that is dominant at any given time, comprising a casing providing a chamber therein and having an inlet and outlet port, a valve movably mounted within said casing for closing one of said ports and being equipped with an elongated stem, a sleeve movably mounted within said casing coaxial with said stem, interlocking connectors coupling said sleeve andv stem when said sleeve is moved in one direction to move said valve into port-closing position but affording. free movement of said sleeve relative to said stern and valve when the sleeve is moved in the opposite direction to free said stem and valve for independent movement through a range of positions, spring means normally urging said sleeve in the direction to close the valve-controlled port, thermal responsive means coupled to said sleeve and operative when subjected to a predetermined temperature to overpower said spring means and move said sleeve longitudinally relative to said stem and against the biasing action of the spring means, thermal. responsive modulator means, and connecting means coupling said modulator means with said stem and being operative to render said stem responsive to said modulator means for free movement through a range of positionswhen said spring means has been overpowered and said sleeve moved against the biasing action thereof and being also operative to render said stern unresponsive to said modulator means when said spring is controlling and is biasing said sleeve in its normal position.

6. The structure of claim 5 wherein said connecting means comprises a lever pivotally secured at one end to said modulator means and at its other end to SBJld stem, said lever having aligned arcuate bearing surfaces on opposite sides thereof, a fixed fulcrum aligned with one of said bearing surfaces, and a second fulcrum aligned With the other of said surfaces and carried by said stem and adapted to engage the bearing surface of said lever and to pivota lly confine the surfaces between the fulcrums when said spring means has been overpowered and said sleeve moved against the biasing action thereof.

7. In a safety-modulating valve structure having a valve selectively responsive to the one of two motivating forces that is dominant at any given time to both control and modulate the fiow of fluid through a flow port, a valve equipped with an elongated stem and being shiftable through a range of positions between open and closed condition, a sleeve movable longitudinally with respect to said stem, connector means coupling said sleeve and stem when said sleeve is moved in one direction to move said valve into port-closing position but when the sleeve is moved in the opposite direction, said interlocking means releasing said sleeve and stem to afford free movement of the stem with respect to the sleeve whereby said valve may then move through a range of positions, means normally urging said sleeve in the aforesaid one direction to close the valve controlled port, thermo responsive means coupled to said sleeve and being operative when subjected to a predetermined temperature to overpower said means and shift said sleeve longitudinally relative to said stem, and thermo responsive modulator means coupled with said stem for moving said valve in response thereto'through a range of positions when the aforesaid means have been overpowered and said sleeve shifted to release said stem.

References Cited in the file of this patent UNITED STATES PATENTS 682,345 Rudd Sept. 10, 1901 1,678,658 Thomas July 31, 1928 1,953,446 Strong Apr. 3, 1934 2,085,300 Dillman June 29, 1937 2,303,128 Koppel Nov. 24, 1942 2,327,582 Dougherty Aug. 24, 1943 2,457,378 Johnson Dec. 28, 1948 

